Mixer knob



FIG. 1 is a perspective view of a mixer knob;

FIG. 2 is a front view of a mixer knob;

FIG. 3 is a back view of a mixer knob;

FIG. 4 is a top view of a mixer knob;

FIG. 5 is a bottom view of a mixer knob; and,

FIG. 6 is a side view of a mixer knob.

The broken lines in the drawings show portions of the mixer knob, that form no part of the claimed design. 

CLAIM The ornamental design for a mixer knob, as shown and described. 